IC‐P‐048: SAMPLE SIZE ESTIMATES FOR SECONDARY PREVENTION STUDIES USING REGIONAL ATROPHY RATES. (1st July 2006) - Cash, David M.; Veale, Thomas; Poole, Teresa; Modat, Marc; Molteni, Erika; Cardoso, M. Jorge; Benzinger, Tammie L.S.; Jack, Clifford R.; McDade, Eric; Bateman, Randall J.; Morris, John C.; Rossor, Martin N.; et al.